The mantra "Doom runs on anything" means the game should be executed by the device in question.
Here, this is not the case, the gut bacteria only acts as a display.
That's the case for a lot of the "doom runs on it" ones, like that pregnancy test. But I like the idea that if it can compute, it can run Doom; if it can display, it can play Bad Apple.
I believe another one of their goals was to grow neurons out of their own human cells and then see who in the lab has the neurons most capable of playing doom. Or maybe verse each other in quake and see whose neurons win.